// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_SOCKET_TCP_SOCKET_WIN_H_
#define NET_SOCKET_TCP_SOCKET_WIN_H_

#include <stdint.h>
#include <winsock2.h>

#include <memory>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/threading/non_thread_safe.h"
#include "base/win/object_watcher.h"
#include "net/base/address_family.h"
#include "net/base/completion_callback.h"
#include "net/base/net_export.h"
#include "net/log/net_log.h"
#include "net/socket/socket_performance_watcher.h"

namespace net {

class AddressList;
class IOBuffer;
class IPEndPoint;

class NET_EXPORT TCPSocketWin : NON_EXPORTED_BASE(public base::NonThreadSafe),
                                public base::win::ObjectWatcher::Delegate {
public:
    TCPSocketWin(
        std::unique_ptr<SocketPerformanceWatcher> socket_performance_watcher,
        NetLog* net_log,
        const NetLog::Source& source);
    ~TCPSocketWin() override;

    int Open(AddressFamily family);

    // Both AdoptConnectedSocket and AdoptListenSocket take ownership of an
    // existing socket. AdoptConnectedSocket takes an already connected
    // socket. AdoptListenSocket takes a socket that is intended to accept
    // connection. In some sense, AdoptListenSocket is more similar to Open.
    int AdoptConnectedSocket(SOCKET socket, const IPEndPoint& peer_address);
    int AdoptListenSocket(SOCKET socket);

    int Bind(const IPEndPoint& address);

    int Listen(int backlog);
    int Accept(std::unique_ptr<TCPSocketWin>* socket,
        IPEndPoint* address,
        const CompletionCallback& callback);

    int Connect(const IPEndPoint& address, const CompletionCallback& callback);
    bool IsConnected() const;
    bool IsConnectedAndIdle() const;

    // Multiple outstanding requests are not supported.
    // Full duplex mode (reading and writing at the same time) is supported.
    int Read(IOBuffer* buf, int buf_len, const CompletionCallback& callback);
    int Write(IOBuffer* buf, int buf_len, const CompletionCallback& callback);

    int GetLocalAddress(IPEndPoint* address) const;
    int GetPeerAddress(IPEndPoint* address) const;

    // Sets various socket options.
    // The commonly used options for server listening sockets:
    // - SetExclusiveAddrUse().
    int SetDefaultOptionsForServer();
    // The commonly used options for client sockets and accepted sockets:
    // - SetNoDelay(true);
    // - SetKeepAlive(true, 45).
    void SetDefaultOptionsForClient();
    int SetExclusiveAddrUse();
    int SetReceiveBufferSize(int32_t size);
    int SetSendBufferSize(int32_t size);
    bool SetKeepAlive(bool enable, int delay);
    bool SetNoDelay(bool no_delay);

    // Gets the estimated RTT. Returns false if the RTT is
    // unavailable. May also return false when estimated RTT is 0.
    bool GetEstimatedRoundTripTime(base::TimeDelta* out_rtt) const
        WARN_UNUSED_RESULT;

    void Close();

    // NOOP since TCP FastOpen is not implemented in Windows.
    void EnableTCPFastOpenIfSupported() { }

    bool IsValid() const { return socket_ != INVALID_SOCKET; }

    // Detachs from the current thread, to allow the socket to be transferred to
    // a new thread. Should only be called when the object is no longer used by
    // the old thread.
    void DetachFromThread();

    // Marks the start/end of a series of connect attempts for logging purpose.
    //
    // TCPClientSocket may attempt to connect to multiple addresses until it
    // succeeds in establishing a connection. The corresponding log will have
    // multiple NetLog::TYPE_TCP_CONNECT_ATTEMPT entries nested within a
    // NetLog::TYPE_TCP_CONNECT. These methods set the start/end of
    // NetLog::TYPE_TCP_CONNECT.
    //
    // TODO(yzshen): Change logging format and let TCPClientSocket log the
    // start/end of a series of connect attempts itself.
    void StartLoggingMultipleConnectAttempts(const AddressList& addresses);
    void EndLoggingMultipleConnectAttempts(int net_error);

    const BoundNetLog& net_log() const { return net_log_; }

private:
    class Core;

    // base::ObjectWatcher::Delegate implementation.
    void OnObjectSignaled(HANDLE object) override;

    int AcceptInternal(std::unique_ptr<TCPSocketWin>* socket,
        IPEndPoint* address);

    int DoConnect();
    void DoConnectComplete(int result);

    void LogConnectBegin(const AddressList& addresses);
    void LogConnectEnd(int net_error);

    int DoRead(IOBuffer* buf, int buf_len, const CompletionCallback& callback);
    void DidCompleteConnect();
    void DidCompleteWrite();
    void DidSignalRead();

    SOCKET socket_;

    // |socket_performance_watcher_| may be nullptr.
    std::unique_ptr<SocketPerformanceWatcher> socket_performance_watcher_;

    HANDLE accept_event_;
    base::win::ObjectWatcher accept_watcher_;

    std::unique_ptr<TCPSocketWin>* accept_socket_;
    IPEndPoint* accept_address_;
    CompletionCallback accept_callback_;

    // The various states that the socket could be in.
    bool waiting_connect_;
    bool waiting_read_;
    bool waiting_write_;

    // The core of the socket that can live longer than the socket itself. We pass
    // resources to the Windows async IO functions and we have to make sure that
    // they are not destroyed while the OS still references them.
    scoped_refptr<Core> core_;

    // External callback; called when connect or read is complete.
    CompletionCallback read_callback_;

    // External callback; called when write is complete.
    CompletionCallback write_callback_;

    std::unique_ptr<IPEndPoint> peer_address_;
    // The OS error that a connect attempt last completed with.
    int connect_os_error_;

    bool logging_multiple_connect_attempts_;

    BoundNetLog net_log_;

    DISALLOW_COPY_AND_ASSIGN(TCPSocketWin);
};

} // namespace net

#endif // NET_SOCKET_TCP_SOCKET_WIN_H_
